.bg {
        width: 1000px;
        height: 600px;
        background-color: #f0ded0;
        border: 6px solid #c07f4b;
        border-radius: 5px;
        /* 白框居中 */
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%); 
}

.bg h2 {
    width: 540px;
    height: 70px;
    line-height: 70px;
    background: #f0ded0;
    text-align: center;
    position: absolute;
    left: 250px;
}

.huanfang {
    width: 500px;
    height: 500px;
    background: #f0ded0;
    list-style: none;
    position: absolute;
    left: 250px;
    top: 70px;
}

.huanfang li {
    width: 150px;
    height: 150px;
    border: 1px solid black;
    float: left;
    font-size: 50px;
    line-height: 50px;
    text-align: center;
}

.huanfang input {
    width: 100px;
    height: 50px;
    font-size: 50px;
    color: red;
    background: #f0ded0;
    border: none;
    text-align: center;
}

#b4 {
    width: 100px;
    height: 30px;
    font-size: 18px;
    background: rgb(236,209,179);
    color: black;
    border: 1px solid #c07f4b;
    border-radius: 2px;
    font-weight: 800;
    position: absolute;
    top: 560px;
    left: 870px;
}
